I know there is a discrepancy between my thin spoke weight and what was reported in the C5 thread. When I weighed the rims I knew others reported 20# so I carefully reweighed each rim and still got 18#. Either my scale is off or theirs is. My weights are from a cheap scale but I was careful with placement and adjustment. I have six of these rims and have tires on and off all of them through track use.

Yeah I noticed that, so I just left all of them on there. There are discrepancies within the C5 list as far as the front wheels go (16 lbs vs 18 lbs) also. I can't vouch for either, which is why I just put it all up there with sources.